Category Archives: Desalination

If California really tried, it could keep a reserve amounting to as much water all of its cities use in a year — about 14 million acre feet. That’s according to a new analysis conducted by the National Resources Defense Council (NRDC) and the Pacific Institute. It’s the “trying” that could prove difficult for the drought-ridden state, because it would take an aggressive, across-the-board effort to save water, reuse water, and capture lost stormwater. Widespread use of available but underused efficiency methods would have to be implemented in the state’s massive agricultural industry, which uses about 80% of allocated water, and throughout urban areas, which use about 20%. That will take strong political will, a lot of cooperation, and financial investment. But it’s worth it, because it will make a huge difference, and you can’t just keep throwing new plans for billion-dollar desalination plants at the problem.

The world has a finite supply of accessible freshwater. By some estimates, less than 1% of the naturally occurring freshwater on earth is accessible to humans; the rest is locked up in ice or too deep and dispersed in the ground for us to get. The phrase “peak water” refers to the point at which we’re consuming available freshwater faster than it can be replenished by nature through the hydrologic water cycle to the usual sources, such as lakes, rivers, and shallow underground aquifers, many of which are already dangerously depleted.

Whether we’re nearing the point of peak water, already there, or well past it is a question under ongoing discussion. One point of confusion is that water volume and use vary widely by region. Some areas are nearing or past peak water, others aren’t. Another factor is that climate change is throwing the status quo of water abundance or scarcity by region into flux. Look at the 2013 research showing that heavy pollution from the U.S. and Europe from the 1960s into the 1980s effectively changed weather patterns, becoming a primary cause of Africa’s long, widespread, and deadly Sahel Drought. What will happen because of today’s pollution from the world’s most prolific sources? (e.g., China).

And those who don’t see water and climate change as parts of the same series of problems should note: “The hydrologic cycle is the climate cycle,” says hydro-climatologist Dr. Peter Gleick, co-founder of the Pacific Institute, in a video interview that lays out overlapping problems. Water, climate change, and energy production are all inextricably linked. In fact, links between water and energy make up the theme of this year’s World Water Day, coming up on March 22.

However close to “peak” we may be, no sustained sense of urgency over water scarcity is apparent in mainstream media. In part this is because water supplies are local or regional, not global, and in part it’s because these problems take a long time — and a much longer attention span than a 24-hour news cycle has — to address. So you see localized articles about regional droughts and potential conflicts over resources, though rarely anything that puts the worldwide water crisis in perspective and looks ahead to cross-cutting solutions (e.g., large-scale renewable-energy power production that requires much less water than nuclear or fossil-fuel-based power, combined with modern and far-reaching conservation measures addressing agricultural, industrial, and residential water use and re-use).

Compared to today’s world, our near-future planet will have double the human population, even more-severe climate change, and yet the same old freshwater, redistributed. Perhaps it’s too easy to push off the worry, as we think we’ll get serious about conservation before it’s too late. Or that governments and industry will join together to provide desalinated water wherever necessary — somehow without the troubling environmental costs of today’s practices — before vast human populations must migrate or die. Or that those fresh and brackish aquifers recently discovered under the oceans will push the point-of-no-return a few decades further into the future. Well, someday, after the fights over the rights, maybe somebody will throw billions at drilling into those aquifers. Because someday they’ll have no choice. And then those reserves will be sucked dry, too.

You might say we have no choice other than to better manage our freshwater.

It’s tempting to see desalination as an eventual cure-all for parched places like California — something that is expensive to implement and run because of energy costs, but worth prioritizing someday. Someday, that is, when there is no other way to get enough freshwater. Many countries have turned to it. Unfortunately, cost is not the only reason to put off desalination projects. Their byproducts, or waste, are bad for the environment and difficult to deal with safely. And in California, critics of seawater desalination would add that far more should be done through conservation before turning to drastic measures.

I recently wrote about solar-powered desalination as an alternative to traditional methods that might help California with its record-breaking drought, focusing on WaterFX and its solar distillation of agricultural run-off water for re-use. On Tuesday, The Guardian‘s Oliver Balch picked up on the story in some depth, referring to renewable desalination projects all over the world, but focusing on WaterFX. That prompted a thoughtful article by environmental journalist Chris Clarke for Southern California’s KCET.org. He asked an obvious and very important question: What about all the salt and other stuff we take out of the water?

At the end of any kind of desalination process, you get leftover piles of salt and buckets of super-salty brine. (Use any measurement metaphor you like, appropriate to scale: piles and buckets; hills and lakes; mountains and oceans.) You get a little freshwater and a lot of leftover crap, some potentially useful and some not, and there’s only so much you can do with it. With WaterFX’s solar distillation, you get brine laced with chemicals and solids from the soil, from fertilizers, motor oil and other sources. The company says it can sell the byproducts, but there’s room for skepticism (and leaky landfills standing by). With seawater, desalination projects tend to filter brine back into the ocean, where it dissolves over time. But brine waste, heavier than seawater, can smother sea life on the ocean floor. And, looking ahead, if huge coastal desalination projects continue to spring up all over the world, how much additional salinity can sea life tolerate? Even in the oceans, a little too much salt can kill.

One thing is relatively clear: Powering desalination with renewable energy should bring down long-term energy costs while providing freshwater. But questions and problems remain. In addition to pollution worries, the timing of when to make the big investment can be tricky. As Clarke points out, a large desalination plant opened in Santa Barbara, Calif., in 1992 because of a drought. But the drought ended, and the plant just sat there because it was too expensive to run in the absence of a crippling water shortage. After its test runs, it never produced a drop of potable water. Now, the largest desalination plant in the western hemisphere is slated for 2016 completion in Carlsbad, near San Diego, at a cost of $1 billion.

As a California resident for 18 years after college, I got to know dry weather pretty well. Right from the start, having arrived in the San Francisco Bay Area in the middle of the 1987 – 1992 drought, I came to see cloudless skies, brown grass and the occasional dryness-induced nosebleed as normal — so much so that the the incessant winter rains that returned years later seemed, briefly, to be freakish.

Now the state is in an even worse dry period — 2013 was the driest year since record-keeping began in the 1840s — and predictable doom-saying has ensued. It’s pretty hard to resist. After all, we know from the geological record that droughts in the area hundreds and thousands of years ago sometimes lasted decades, or even a century. Droughts of that magnitude have ended civilizations. See the Anasazi, wiped out in the Southwest about 800 years ago.

“Driest year since the 1840s” doesn’t sound good, but the reality is, indeed, probably worse. UC Berkeley paleoclimatologist B. Lynn Graham says old tree rings indicate the area hasn’t been so desiccated since 1580, 434 years ago. She points out that the past 150 years of modern development have been comparatively wetter years than some previous, longer, drier, and, arguably, “normal” periods, as noted above. Those long, dry periods could return.

An interesting characteristic of the drought is the proximate cause pointed out by meteorologists: a ridge of high pressure off the coast is “feeding off itself,” refusing to move or dissipate as it blocks wet weather from reaching land. The timing is especially bad because California needs winter storms to replace its freshwater, in the form of rains and especially snow melt from the mountains. Sounds like an effect of climate change, something that’s easy to believe but hard to prove.

It takes a lot of water to generate power through various processes, and it takes a lot of power to extract, treat and deliver water. Yet, according to the World Bank, energy planning and development decisions are often made without regard to current and future water shortages. Its plan is to offer proactive, cross-sector advice on energy and water resource management planning, tailored according to a given country’s resources, modeling experience, and political and institutional realities.

Why go to all that trouble? Because near-future projections paint a disturbing picture. Today more than 780 million people don’t have enough access to potable drinking water, and about 1.3 billion lack electricity, according to estimates. In a world with a fixed and finite amount of freshwater but a surging population, global energy consumption is expected to swell 50% by 2035, while the energy sector’s use of water may increase by 85%. That means worsening water shortages, and, as noted in a previous post, climate change will make the situation even more dire in certain areas.

A Chinese company and a university research team said Tuesday they will begin desalinating sea ice on a large scale to make freshwater for drinking and use in agriculture and industry, the Xinhua news agency reports.

With technological development, the cost of desalination is falling, which makes this kind of industrial-strength effort more feasible than it used to be. It helps that sea ice has much less salt than seawater: 0.4 to .0.8% versus 2.8 to 3.1%, according to the researchers, who are from Beijing Normal University.

Using newly developed equipment, including machinery to break and gather ice, Beijing Huahaideyuan Technology Co. says it expects annual output of 1 billion cubic meters of freshwater at 0.1% salinity by 2023.

When you hear about desalination, it’s usually about a large-scale effort to transform seawater to freshwater through the process of reverse osmosis. In other words, an industrial plant is built in a terribly dry place at considerable expense, and salt water is pumped in and forced through membranes to create much-less-salty water (to oversimplify). But there is another, completely different process that separates salt and other things from water using a “solar still.”

Solar desalination technology isn’t new, but a company called WaterFX* is trying to put it to a new use in water-challenged California, and, potentially, everywhere, according to an interesting article in Forbes (link below). The company’s effort is about selling its scalable Aqua 4 system to growers and water districts, who can use it to recapture, purify and reuse agricultural run-off (that is, the copious amount of water used for irrigation that picks up salts, fertilizer and other impurities that make it problematic to reuse without damaging crop yields). The company’s small-scale pilot project with California’s Panoche Water District was able to produce nearly 500 gallons of clean water per hour, and the district plans to launch a larger project with the company, according to the article below.

OK, it may not be as glamorous or as self-important as the Academy Awards, aka The Oscars, but the International Desalination Association (IDA) exists and it gives out awards. That’s two new things I learned today.

*(NGO, or non-governmental organization; the abbreviation is used more commonly than the spelled-out version in the development world, e.g., the world of the United Nations and various other regional and international aid organizations.)

With communities in Chile’s Atacama Desert — one of the world’s driest — competing with copper mines for dwindling water supplies, some of the country’s lawmakers have submitted a bill that would force mining companies to use desalinated Pacific Ocean water, according to reports in Bloomberg and Mining.com.

A statement from Chile’s Chamber of Deputies, the lower house of the National Congress, calls for mining companies that use 150 liters (40 gallons) of water per second to begin using desalinated water in order to preserve freshwater for other uses. Some mining companies already use desalinated water, others don’t. There is no word yet on when the upper house, the Senate, will address the legislation.

One third of the world’s copper supplies comes from Chile, and one third of the Chilean government’s revenue comes from copper exports — making mining one of the country’s most important industries as well as one of its biggest users of water. According to a report in BNamericas, the industry’s need for water is expected to increase by 38 % by 2021.